Short-ranged attractions in jammed liquids: How cooling can melt a glass
Abstract
We demonstrate that an extended picture of kinetic constraints in glass-forming liquids is sufficient to explain dynamic anomalies observed in dense suspensions of strongly attracting colloidal particles. We augment a simple model of heterogeneous relaxation with static attractions between facilitating excitations, in a way that mimics the structural effect of short-ranged interparticle attractions. The resulting spatial correlations among facilitated and unfacilitated regions give rise to new relaxation mechanisms that account for non-monotonic dependence of relaxation times on attraction strength as well as logarithmic decay of density correlations in time. These unusual features are a simple consequence of spatial segregation of kinetic constraints, suggesting an alternative physical perspective on attractive colloids than that suggested by mode-coupling theory. Based on the behavior of our model, we predict a crossover from super-Arrhenius to Arrhenius temperature dependence as attractions become dominant at fixed packing fraction.
Keywords
Cite
@article{arxiv.cond-mat/0402673,
title = {Short-ranged attractions in jammed liquids: How cooling can melt a glass},
author = {Phillip L. Geissler and David R. Reichman},
journal= {arXiv preprint arXiv:cond-mat/0402673},
year = {2009}
}